1. Field of the Invention
The present invention relates to an information record medium such as an optical disk of a high recording density type, which is capable of recording information such as video information, audio information and the like at a high density, and which is represented by a DVD (Digital Video or Versatile Disk). The present invention also relates to a recording apparatus for recording the information onto the information record medium, and a reproducing apparatus for reproducing the information from the information record medium.
2. Description of the Related Art
Conventionally, a so-called ID (Laser Disk) and a so-called CD (Compact Disk) are generalized as optical disks, on which information such as video information, audio information and the like is recorded.
On the ID or the like, the video information and the audio information are recorded together with time information indicating a time at which each information is to be reproduced with respect to a reproduction start position, which each ID or the like has, as a standard position. Thus, other than a general normal reproduction to reproduce the recorded information in the order of recording, various special reproductions are possible, such as a reproduction to extract and listen to an only desirable music out of a plurality of recorded musics, a reproduction to listen to the recorded musics in a random order and soon, in case of the CD, for example.
However, there is a problem that, according to the above mentioned LD or the like, a so-called interactive and variegated reproduction is not possible in which the audience can have a plurality of selection branches as for the video or audio information to be displayed or sound-outputted and in which the audience can select them to watch or listen to it.
More specifically, when watching and listening are directed to a foreign movie recorded on an LD, it is impossible to select a language used in a superimposed dialogue displayed on a screen (for example, to select superimposed dialogues in both of the Japanese and original languages) to display them on a screen, or when listening is directed to music recorded on a CD, it is impossible to select a kind of sound or voice in the music (for example, to make alternate selection of lyrics in English language version and Japanese language version for listening).
A movie production has often been subjected to different cutting processes to prepare the same-titled movies in different versions such as a theater version, an original version and the like. When there has been made an attempt to record simultaneously the same-titled movies in different versions on an LD or the like, it has been necessary to make a duplicate record of common portions thereof in order to permit reproduction without interruption. Accordingly, the same-titled movies have actually been compelled to be recorded on separate disks. It has therefore been impossible for a user to select a different version of the same-titled movies to enjoy it in a single disk.
It has also been impossible to record a plurality of simultaneously advancing pictures in a single story. It has therefore been impossible to make a free choice of, for example, one of a plurality of pictures obtained at different camera angles to enjoy it.
The interactive and variegated reproduction can be achieved by recording, on a navi-pack in an interleaved unit described later, amend address of the interleaved unit and a start address of the next interleaved unit, and reading them out.
When the navi-pack cannot be read out or a reading-out error occurs for some reason or other, it becomes impossible to identify which data already being selected (for example, the "theater version" or the "original version" in the above-mentioned example) corresponds to data (real time data) on a disk, which are now being read out, and subsequent reproduction cannot be achieved. When information for a period of one hour is recorded on an interleave structure, only a failure in reading out the first logical address may cause reproduction to be completely impossible for a subsequent period of one hour.